Intermittent Starting Issue (No Crank) - 2012 XKR 5.0 (X150)

[BigCatV8]

Hi All,

New to the forum, so please let me know if this isn’t the right place to post.

I own a 2012 Jaguar XKR 5.0 SC (X150) which has developed an intermittent starting issue. When I go through the normal starting procedure, I get a single click but no crank from the starter motor. Naturally, this appears to not be receiving the voltage needed to crank.

Please Note: I’ve already replaced the battery, and spent quite a bit of time and money diagnosing this problem with various garages (including some JLR specialists), but so far, no luck. The following parts have just been replaced with OEM parts from JLR (thankfully most under warranty).

Parts replaced over the past couple of months:

• Battery (Yuasa)
• Starter motor (OEM)
• Battery negative terminal loom (OEM)
• Charged battery to full on CTEK charger, and issue persists even with a full battery or jump pack.

Originally, the fault threw up DTC codes related to the camshaft position sensors (both banks), but I’ve since been told that’s a false flag caused by low voltage during cranking. My readings show 12.6V at the rear battery, but only around 11.3V reaching the front — clearly indicating voltage drop somewhere along the line.

I’m now troubleshooting this myself on the driveway. The warranty company were great and covered most of the above work, but as the policy has expired (and can’t be renewed with an ongoing fault), I’m on my own for the next steps. Interestingly, this weekend I've spotted a small amount of water ingress, in the right-hand side boot where the FM antenna booster module (C2P2761) sits. I've removed the module and the car has started perfectly a couple of times. This is unusual given recent months, but certainly welcome!

Has anyone experienced this issue before or can point me in the right direction on what to check next? - One area of focus now is the earth straps... However, I cannot find an easy to follow diagram of where the main earth straps are on the car. I have spoken with JLR parts locally, and C2C8864 - Jaguar Earth strap is no longer available.

Any advice or insights would be greatly appreciated.

Kind regards,
Mick